Does a Morphological Adjustment during Tsunami Inundation Increase Levels of Hazards?

摘要

Tsunamis are able to move large amounts of sediment during their inundation process. However, previous studies conducted to assess tsunami hazard have not considered tsunami-induced sediment transport in their simulations, although it is possible that morphological adjustments during tsunami inundation increase the levels of hazard. In this paper, we present a model which is able to simulate sediment processes caused by tsunami action. The model is validated by comparing results to an experiment of sediment transport under breaking solitary waves. Finally, the model is applied to the simulation of sediment transport over a typical barrier island geometry, and we study the resulting changes in tsunami runup on the mainland behind the barrier, as compared to fixed bathymetry/topography conditions. We show that considering morphological changes during tsunami inundation modeling can increase the runup on the mainland behind the barrier. We conclude that assuming a fixed bathymetry when modeling tsunami coastal hazard may lead to underestimating runup and inundation values and cause errors in estimating the tsunami inundation line.